The invention relates generally to apparatus for harvesting stalk crops such as corn or the like and, more particularly, to an improved harvester head.
German Patent Publication 3838979 A1 and German Patent 4344669 disclose apparatuses for harvesting stalk crops with snapping units including at least one feed and snapping roller below a snapping gap. The snapping gap has product-transporting conveying elements on conveyor chains. For lateral yielding of the conveying span of the chains to be avoided, the chains have guide elements which at least partially contact the revolving chains and are arranged releasably on a common main body. Such an arrangement is shown in corn picker (Maispfluucker) brochure of CLAAS KGaA, no. 190.146.1. To compensate for gradual stretching of the chain, the conveyor chains are provided with tensioners which in general allow tensioning of the conveyor chains against the action of a spring. In order for reliable stalk feeding to be continued at all times, the snapping gaps of each snapping unit can be adjusted within a given range to the stalk diameter of the crop. Generally one of the snapping gap-forming snapping plates is stationary, and the other is displaceable in its position transversely to the direction of travel by hydraulic or mechanical displacement mechanisms. The guide elements of the chains, the chain tensioners, and the parts which hold the displacement mechanism of the snapping plates are essentially constructed as bent sheet metal and welded parts which are releasably attached to a common main body. This construction causes high assembly costs. Substantial drawbacks of snapping units designed in this way include poor accessibility of the fasteners during assembly or repair, a large number of necessary component parts, and the resulting high weight of the front attachment.